Method for making stems for tipless lamps



April 6 1926.

J. J. HIGGINS METHOD FOR MAKING STEMS FOR TIPLES S LAMPS Filed May 27, 1921 Fla]; FIGQ- FIGS- INVENTOR JOHN J /-//c G/NS ATTORNEY Patented Apr. 6, 1926.

UNITE-D STATES-PATENT orrlcsq JOHN Josnrn HIGGINS, 01? EAST ORANGE, NEW JERSEY, ASSIGNOB TO WESTHGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

unrnon non maxmo ems r03 'rIrLEss LAMPS.

. Application fled lay 27, 1921. Serial Io. 473,024.

To all whom it may concern:

Be it known hat I, J OHN J osnrn I-Imoms, a citizen of the United States, and a resident of East Orange, in the county of Essex and 5 State of New Jersey, have invented a new and useful Improvement in Methods for Making Stems for Tipless Lamps, of which the following is a specification.

This invention relates to a method of manufacturing stems for incandescent electric lamps of the tipless type.

An object of the invention is the provision of a'novel method of so joining together the several parts which constitute a lamp stem as to materially reduce such difficulties as cracking and breaking thereof.

Another object-is the formation of the several parts to be combined to form a unit structure so that the surfaces at the junclo tures of the several parts shall'be curved,

thus eliminating sharp an' les which are undesirable in the glass-wor in industry.

Other objects of the invention will be apparent from the following description. A

In the manufacture of incandescent lamps of the so-called tipless type, it has been the custom to join an exhaust tubewith thestem or flare tube in order to facilitate the exhausting of the lamp bulbs. Considerable 0 diflieulties are encountered in rforming this operation; the main di culties .of'.

cracking and br aking being apparently due to excessive str ins set up during the sealing together of the several parts of the stem to form a unit structure. Such defects increase the cost of manufacturing operations to an unwarranted. extent. The invention hereinafter set forth is directed to a method of so. joining together the several parts of a tipless lamp stem as to avoid the ditliculties above mentioned.

The drawings accompanying 7 this specification illnstratethe condition ofa stem at variousstages of manufacture, and, in these drawings,

Fig. 1 is a view, partially in section, of'

the assembly of the various ing a stem; y

Fig. 2 is a view, partially in section, of the partsafter being joined;

Fig. 3 is a sectional view of .thestem showing the curved surfaces at the junctures of parts constitutthe several parts and showing an air-exhaust passageway. v i

Fig. 4 .is a side elevational view of the stem showing,-in outline, the exhaust tube and the passageway. I

The description of'the method will be set forth in connection with the formation of a tipless lamp stem wherein anexhaust tube 1s joined in the press or seal and this tube the flare tube. The ress also includes the .ends of theflare tu e, the arbor and the leading-in conductors. The stem formed by this method provides for the step of drawmgor pulling some part ofthe stem while the glass in the joint or seal is in molten is preferably positioned concentrically in v .by any desirable source of heat such, for instance, as the well known pointed fires (not shown The several well known parts comprising a stem are, a tube 1 having a flared portion 2, an arbor 3 for supporting the filament, leading-in conductors. 4 and an exhausttube 5 provided with a-constricted' portion 6' for tipping off after the lamp ulb has been exhausted. These several lapped position, as illustrated in Fig'. 1.

'After the parts have been assembled in a stem-making machine, preferably in the relation shown, and the fires have been vapplied to heat the ends-or overlapped p01- parts are preferably assembled. in overtions to a molten condition, the parts are pressed together in any suitable'manner in order to form the stem. The shape of the joint or press may have any desired contour,jaccording to the form of the press jaws employed. In this embodiment, the press preferably is formed in the shape of an ellipse which may be readily appreciated by reference to Figs. 2 and 4. It is to be noted that the surfaces '7 at the juncture of the flare tube andthe exhaust tube are sharp and form an-acute angle, as illustrated in Fig. 2; also that the surfaces 8 at the juncture of the arbor with the end of the press also form sharp angles.

The next step in performing the method is to reposition or stretch the glass at the joint. or press. This step permits the sec tion of the glass at the' press to be made more uniform and to reduce the amountof glass in the press itself. This repositioning or stretching may be performed. in any desired manner, however, for the convenience.

glass in the sealed portion proper has been reduced by drawing the exhaust tube u ward and has carried part of the glass of the press therewith and, in addition, the surface at the juncture of the flare and exhaust tubes is curved, as illustrated at 9, and the surface at the juncture of the arbor with the lower portion of the press is curved as illustrated at 10. It is to be noted that a constriction 11 has been formed in the lower end of the exhaust tube but this is not detrimental so long as the opening in the exhaust tube is not closed.

After the stepof stretching or pulling has been completed, compressed air 1s admitted tothe exhaust tube and the glass at the press, being still in a plastic condition, is forced aside and an openingor passageway 12 leading from the exhaust tube, is formed in this press or joint as illustrated in Figs. 3 and 41 This opening provides the passageway for the air drawn-from the lamp bulb to the exhaust pump during the operation of exhausting the lamps.

By forming the stem in accordance with this method, the. glass forming the stem is drawn to provide a more uniform cross-section at the press or seal and provides for curved surfaces between any two of the parts comprising the stem, and the utilization of this method has been of distinctive advan tage in substantially avoiding the cracking and breakin difliculties which have been experienced in the manufacture of stems by other methods.

This method, although described in 'eonnection with the formation of a particular article, is not to be considered as being limit ed to this particular use but may be employed to manufacture other articles of a similar nature.

What is claimed is:

1. The method of forming a stem for an incandescent lamp which consists in as sembling individual glass parts, heating and pressing together the said parts, ell'cctinga relative bodily movement of said parts to reduce the amount of glass in the seal and to alter the surface contour thereof.

2. The method of forming a stem for an incandescent lamp which consists in assembling individual glass parts including 'an exhaust tube, heating and ,pressing together to unite portions of said parts, working the glass to provide rounded surfaces at the union of said parts and then forcing air down one of said parts to provide a passage in said'union.

3. The method of forming a stem which consists in assembling individual glass parts, heating and pressing portions of said parts together, working the glass to form curved surfaces at the juncture of the parts and forming a passage through the compressed portion.

4. The method of forming the stem of an incandescent lamp which consists in assembling the component parts of the stem, locally heating said parts, pressing the heated portions to unite the parts, changing the relative positions of the parts to work the heated portion while still plastic and in forming a passage through the union of said parts.

5. The method of forming a stem for an incandescent lamp which consists in assembling a flare and an exhaust tube, an arbor and leading-in conductors, heating and pressing together predetermined portions of the named parts, pulling said exhaust tube and admitting compressed air therethrough to form a passage way through the pressed portions.

6. The method of forming a stem for an incandescent lamp which consists in assembling, in overlapped position, the ends of an exhaust and a flare stem tube, an arbor and leading-in conductors, heating the overlapped portions of said named parts, press ing the same into integral relation, pulling said exhaust tube to remove some of the 'glass from the formed press and blowing an opening in said press by introducing air, under compression, into said exhaust tube.

7 An incandescent electric lamp stem comprising an'exhaust tube, a flare tube and an arbor united at their ends in a common mass and having a constricted portion at a I point adjacent to the-mass.

8. An incandescent electric lamp stem comprising an exhaust tube, a flare tube and .an arbor fused together in a common mass,

10. A stem for an electrical device comprising an exhaust tube and a flare tube united at their ends in a mass and having a constricted portion at a point adjacent to the mass. 11. In an electrical device, a stem comprising a flare tube and an exhaust tube therein,

the walls of said tube being integrally connected by a union having a chamber blown therein communicating with said exhaust 1 tube, another aperture in the wall of said chamber and a constricted portion in said.

exhaust tube adjacent saidchamber.

In testimony whereof, I have hereunto Subscribed my name this 25th day of'May 1 

